Casement, double-hung, sliding, and other windows are common and generally known. These windows and their associated operators provide ventilation and interior/exterior access by generally displacing a window sash relative to a surrounding frame structure through slidable or pivotal movement. In some applications, however, such displacement is undesirable. For example, displacement of a sash relative to a surrounding frame can be esthetically displeasing from the exterior, particularly on large buildings with many windows. A casement window, in which the window typically pivots outward relative to the frame, can be impractical or dangerous in areas of high wind.
Projection, or stand-out, windows are also known and can be used where it is desired to minimize the visual impact of open windows relative to the rest of a structure, or where it is impractical or infeasible to use the windows described above. A projection window generally provides a horizontal displacement of the sash relative to the surrounding frame, thereby providing a trickle ventilation around the entire window.
For example, U.S. Pat. Nos. 497,296 and 531,244 disclose early projection-type windows. These windows were suited for ventilating railway passenger cars, among other applications.
U.S. Pat. No. 2,374,618 discloses a sash movably supported on a window frame at each of opposite vertical sides thereof by a link arrangement comprising a long bar and short bars, the two latter respectively lying at opposite sides of the long bar. The construction described and depicted permits the sash adjustably to be moved bodily away from the window frame and into various positions.
A stand-out window opening mechanism is described in U.S. Pat. No. 4,866,882. The window opening mechanism moves the entire window sash outwardly from the window frame in a plane parallel to the plane of the frame. The mechanism for accomplishing this includes a pair of pivoted L-shaped lever arms on each side of the window. The short legs of these lever arms are substantially shorter than the long legs, and the ends of the short legs are pivotally attached to the window frame relatively close together. An operating mechanism is provided for moving the elbows of the lever arms toward and away from one another, and the ends of the long legs of the arms are pivotally connected at spaced apart points on the window sash. As the elbows of the levers on both sides are moved toward one another, the window sash is pulled toward the frame. When the elbows are moved away from one another, the pivoting action of the lever arms causes the window sash to be moved outwardly from the frame to provide a “stand-out” opening of the window.
U.S. Pat. No. 6,070,637 discloses a horizontally openable window. The window comprises a screen-like enclosure between the window casement and the window frame that limits the amount of moisture or dust that can enter through the window when in an open position.
Projection windows such as those identified above that are presently known include complex mechanisms for operating the window and supporting the sash in both extended and retracted positions. These mechanisms can limit the applications of projection windows because they occupy more space and require a deeper window frame. Further, in some applications it may still be desired to operate a projection window like a casement window, opening and closing only one vertical side of the window on a pivot relative to the frame, or to similarly pivotally open and close only one horizontal side.
For the foregoing reasons, there is a need for a projection window operator that is compact and secure. There is also a need for a projection window operator that provides for selectable opening and closing of the window in various other configurations.